Analysis - This assessment may surprise you coming from someone who spends his professional life criticising and critiquing politicians: Over the past 20 years we have been among the best governed countries in the world.

New Zealand politics in 2018 wasn't all about scandal and leaks, Guyon Espiner writes. Photo: RNZ

No, it's not just the festive glow. Under successive governments in the 21st century New Zealand has ranked near the top of many indices which measure social, economic and environmental status. One, which groups nine 'pillars of prosperity', is the Legatum Prosperity Index. New Zealand was second only to Norway for 2018.

So having the spent the year finding weak points to stress-test the politicians on - and, hey that's my job - in the spirit of Christmas generosity let's look for the good. We'll have a couple of flicks along the way - but only a couple. Promise.

Labour wasn't expecting to govern and early on it didn't look ready to govern. Ministers were ill-prepared for government or ill-suited to it. Two were sacked. But Labour finishes the year looking more stable and coherent. Ministers Andrew Little, Kris Faafoi and David Parker have performed strongly.

But the core of a government is the bond between finance Minister and prime minister. Grant Robertson has done much to shed the albatross always around Labour's neck: a perception of poor economic management. Unemployment is below 4 percent, debt is below 20 percent of GDP and a surplus of more than $7.6 billion is forecast by 2022.

It could be blown off course by international events next year - and yes you can argue he should be spending more - but Robertson is on track to position Labour well for the 2020 election.

Jacinda Ardern is Labour's greatest asset. Former Prime Minister Mike Moore said in the 9th Floor series that leaders are like a canvas that people project their hopes and dreams on. She is that for many people. That's the public role. But arguably her work behind the scenes is equally important. She has managed a coalition with the Greens and New Zealand First. That's a simple sentence. Benign even. But that task was considered impossible by many prior to 2018. It hasn't always been smooth but it could have been a lot worse. That will remain a challenge for 2019.

But the biggest challenge for Labour? The same challenge it always has: tax. And it's the same question as in 2011, 2014 and 2017: will there be a capital gains tax (CGT)?

National of course hopes Labour will propose a CGT because they would love to oppose the tax and depose the government over it. National has had significant challenges this year. The Jami-Lee Ross rupture was explosive. But when the ash and smoke cleared the damage was limited.

National Party leader Simon Bridges is still standing. He's not personally popular and those ratings probably won't change. But to have his party in the mid-40s in the Colmar Brunton poll is remarkable (and no, I'm not convinced that selective leaks of internal polls tell 'the real story').

The greatest challenge for National in 2019 will be staying relevant - and remembering that the enemy is in front of them and not within.

New Zealand First turned 25 this year and has other reasons to celebrate 2018. Forty years after entering Parliament NZ its leader, Winston Peters, is more influential than ever. His party prised billions from Treasury for foreign affairs and the Problem Gambling Foundation. On foreign policy Peters faltered badly over the Russia FTA but has largely been solid in his second stint in the portfolio. The challenge for him in 2019 will be managing the increasingly fraught relationship with China.

The Greens looked swamped by New Zealand First at times but can also be happy with 2018. It wasn't a big bang approach, more of a big ban approach. Oil and gas exploration and single use plastic bags are banned. Those are big changes. It's hard to imagine them happening without the Greens in government.

Act? Well it's only in Parliament because National lets David Seymour win Epsom. But hey, it's Christmas and Seymour is a talented, bright MP who is a human headline when he puts his mind to it.

I'll leave the assessment of his dancing skills for you. I'll also leave you with a question about MMP to bring us back to where we started. Consider this (unlikely but not far-fetched) scenario. In 2020 National lets Act wither. The Green vote drops 1.5 points and the New Zealand First vote drops 2.5 points. You'd be back to an FPP style, two party Parliament of National and Labour. Would our world rankings remain?

A taped conversation between former National MP Jami-Lee Ross, party leader Simon Bridges and deputy Paula Bennett shows the leadership tried to keep their internal problems out of the public eye. Video